Big Blue's Transformation

[ArdWrknTrk]

Gary, are you just using the dash oil pressure gauge? If so do you have a mechanical one you can connect? If for some reason the oil pressure is fluctuating due to any of a number of factors it could be causing the switch to be opening and closing. You didn't have the pulses when you jumped the switch to check and set the pressure, so something is now causing this.

That's an intriguing idea Bill.

I don't like the implications, but it should be easy enough to see if the relay is cycling.

With a voltmeter, or just holding a finger to it.

On thinking about this for a second, I recall that when I first implemented the ground side blower relay I had somehow set up a feedback loop and it was chattering.

I know Gary's more of a wiz than i am, but is he using his PDC, or the factory harness for the pump relay?

[85lebaront2]

That's an intriguing idea Bill.

I don't like the implications, but it should be easy enough to see if the relay is cycling.

With a voltmeter, or just holding a finger to it.

On thinking about this for a second, I recall that when I first implemented the ground side blower relay I had somehow set up a feedback loop and it was chattering.

I know Gary's more of a wiz than i am, but is he using his PDC, or the factory harness for the pump relay?

Jim, the reason I asked that is from personal experience. I don't remember which engine it was, I'm thinking either my Falcon 260 or Cobra 289 in my GT350 that cracked the cup plug that Ford inserts open end in over the pressure relief valve spring. Since it is a blind cap, there is a probably 1/8" passage from the back side of the relief valve and the pump inlet. The cracked cap was allowing the pump to draw air in causing a very erratic oil pressure on the factory 5V thermal gauges it wasn't obvious, but on a mechanical gauge you could see the pointer vibrate which is the reason the better gauges have a damper on them so they don't vibrate at idle when the actual pulses from the pump manifest themselves.

Item for your store of arcane and occasionally useful information, on the later Bricknose and Aeronose trucks, it is possible to have a working oil pressure gauge. On the circuit board for the cluster, there is cut strip between the sender input and the signal pin on the gauge (they have 3 pins, Ignition Power, Signal and Ground) there is a resistor across this "gap" that when the signal lead is grounded by the oil pressure switch puts the "gauge" at roughly 1/2 scale. If this "gap" is bridged with a piece of wire and one of the old "dome" style senders used, it becomes a working gauge and is very responsive to changes in pressure.

[Gary Lewis]

That's an intriguing idea Bill.I don't like the implications, but it should be easy enough to see if the relay is cycling.With a voltmeter, or just holding a finger to it.On thinking about this for a second, I recall that when I first implemented the ground side blower relay I had somehow set up a feedback loop and it was chattering.I know Gary's more of a wiz than i am, but is he using his PDC, or the factory harness for the pump relay?

I do have two gauges installed, as shown below, and both of them are connected on the same tee as the oil pressure switch. I don't think the pressure could be dropping that much to drop out the switch. But, I guess that is possible. So here's the test I am planning on doing:

 

1. Put my jumper/switch on the oil pressure switch and, with the key on, bring the pump on w/o the engine running to see what the pressure does. I assume it'll settle at 5 psi w/o bouncing, just like it did before.

 

Then start the engine to see what the pressure is doing. I'll bet it bounces as I've done nothing that would fix it.

 

While the engine is running, and the gauge is presumably bouncing, close the jumper/switch to short across the oil pressure switch. If that is the problem the gauge should stabilize.

 

I'm betting that shorting across the oil pressure switch does nothing. I'm guessing that the issue is that when the float closes the pressure spikes because the regulator can't react quickly enough. And I'll bet the float is chattering.

 

If that is the case then maybe the deadhead regulator will fix that?

 

[85lebaront2]

I do have two gauges installed, as shown below, and both of them are connected on the same tee as the oil pressure switch. I don't think the pressure could be dropping that much to drop out the switch. But, I guess that is possible. So here's the test I am planning on doing:

 

1. Put my jumper/switch on the oil pressure switch and, with the key on, bring the pump on w/o the engine running to see what the pressure does. I assume it'll settle at 5 psi w/o bouncing, just like it did before.

 

Then start the engine to see what the pressure is doing. I'll bet it bounces as I've done nothing that would fix it.

 

While the engine is running, and the gauge is presumably bouncing, close the jumper/switch to short across the oil pressure switch. If that is the problem the gauge should stabilize.

 

I'm betting that shorting across the oil pressure switch does nothing. I'm guessing that the issue is that when the float closes the pressure spikes because the regulator can't react quickly enough. And I'll bet the float is chattering.

 

If that is the case then maybe the deadhead regulator will fix that?

 

Maybe so, it worked well on Pacers to fix their hot start problems.

[ArdWrknTrk]

I do have two gauges installed, as shown below, and both of them are connected on the same tee as the oil pressure switch. I don't think the pressure could be dropping that much to drop out the switch. But, I guess that is possible. So here's the test I am planning on doing:

 

1. Put my jumper/switch on the oil pressure switch and, with the key on, bring the pump on w/o the engine running to see what the pressure does. I assume it'll settle at 5 psi w/o bouncing, just like it did before.

 

Then start the engine to see what the pressure is doing. I'll bet it bounces as I've done nothing that would fix it.

 

While the engine is running, and the gauge is presumably bouncing, close the jumper/switch to short across the oil pressure switch. If that is the problem the gauge should stabilize.

 

I'm betting that shorting across the oil pressure switch does nothing. I'm guessing that the issue is that when the float closes the pressure spikes because the regulator can't react quickly enough. And I'll bet the float is chattering.

 

If that is the case then maybe the deadhead regulator will fix that?

 

I'd still check for a chattering fuel pump relay, Gary.You'd only have to parasite a test light on the pump power wire.It doesn't need to be oil pressure that is cycling the pump, as I said.Bill, I know all about the 'Ford fix' for a fluctuating oil pressure gauge being to replace the sender with a switch, and add a 20 ohm resistor.Screw those guys for not just making it an idiot light.Deceptive 'stagecraft' in order assuage customers rightful concerns is an outright lie, in my playbook.

[Gary Lewis]

I'd still check for a chattering fuel pump relay, Gary.

You'd only have to parasite a test light on the pump power wire.

It doesn't need to be oil pressure that is cycling the pump, as I said.

Bill, I know all about the 'Ford fix' for a fluctuating oil pressure gauge being to replace the sender with a switch, and add a 20 ohm resistor.

Screw those guys for not just making it an idiot light.

Deceptive 'stagecraft' in order assuage customers rightful concerns is an outright lie, in my playbook.

Well, I just did steps 1 and 2, and on both the fuel pressure came up to 5 psi perfectly.

I think it is still dropping a cylinder or two at idle, but didn't run it long enough to even get the choke off as I want to pull the plugs.

But, I also found a oil spot on the driveway (yes it set out last night) right under the front of the engine crossmember. There's dampness on the front of the crossmember, and the fluid looks like Royal Purple, which probably means I have a leak in the connections at or around the P/S pump.

[ArdWrknTrk]

Well, I just did steps 1 and 2, and on both the fuel pressure came up to 5 psi perfectly.

I think it is still dropping a cylinder or two at idle, but didn't run it long enough to even get the choke off as I want to pull the plugs.

But, I also found a oil spot on the driveway (yes it set out last night) right under the front of the engine crossmember. There's dampness on the front of the crossmember, and the fluid looks like Royal Purple, which probably means I have a leak in the connections at or around the P/S pump.

Gary, do you have the cooler loop on the front of the crossmember?

 

[Gary Lewis]

Gary, do you have the cooler loop on the front of the crossmember?

Yep

[Gary Lewis]

Gary, do you have the cooler loop on the front of the crossmember?

Yep

Plugs 1 - 4:

Plugs 8 - 5:

And that plug #7 a bit closer:

[ArdWrknTrk]

Plugs 1 - 4:

Plugs 8 - 5:

And that plug #7 a bit closer:

Ah!

Your favorite mystery grease has given you a dead hole.

(Could have found it with the IR)

But 2 & 5 look pretty sooty.

Any idea why they seem so much worse than all the others?